Cardiac rhythm management (CRM) devices include implantable or ambulatory devices such as pacemakers, cardioverter defibrillators, and devices that provide a combination of pacing and defibrillation, including cardiac resynchronization therapy. The devices can be used to detect worsening heart failure through internal monitoring of a patient's condition, as well as to treat patients using electrical therapy. The devices can include electrical leads in communication with sense amplifiers to monitor electrical heart activity within a patient, and often include sensors to monitor other internal patient parameters.
Biomarker assays, such as B-type natriuretic peptide (BNP), can also be used to detect worsening heart failure. BNP is a polypeptide secreted by the ventricles of the heart in response to excessive stretching of cardiomyoctes. BNP is co-secreted with an amino acid called NT-proBNP, which is biologically inactive. Both BNP and NT-proBNP levels in the blood can be used for screening and diagnosis of heart failure, and can also be useful to establish prognosis in heart failure, as both biomarkers are typically higher in patients with worse outcome.